Transmission system



Filed Aug. 1, 1938 Inventor: Hamshein rich Verse by Z/ x is Attorney.

Patented Feb. 21, 1939 UNITED STATES PATENT OFFIQE TRAN SIWISSION SYSTEM tion of New York Application August 1, 1938, Serial No. 222,480 In Germany February 22, 1937 Claims.

My invention relates to direct current power transmission systems and more particularly to such systems utilizing electric valve translating apparatus at the transmitting and receiving ends.

In direct current power transmission systems utilizing electric valve translating apparatus at the transmitting and receiving ends it has been found diflicult to place the transmission system into operation in such systems where no neutral wire has been provided and more particularly in such systems where the electric valve translating apparatus utilizes electric arc discharge valves of the type described in a book by Erwin Marx entitled Lichtbogenstromrichter published in Berlin in 1932, and in United States Letters Patent No. 2,074,930 granted March 23, 1937, upon the application of Erwin Marx. In such systerns it has been customary to provide a continuous flow of gas, such as air, between the electrodes of the valves. In some of the arrangements the principal pair of electrodes has been provided with an auxiliary electrode which serves as starting or ignition electrode. It has been customary in such arrangements to operate the valves with an ignition moment displaced by where m. equals the number of phases in each translating apparatus, in order to obtain the advantages of a 2m phase direct current voltage ripple. If the time during which the auxiliary arc operates and the type of rectifier is very short or if in the instance of the usual gaseous type electric valve the ignition impulse is very short, then such transmission system cannot start up in the absence of suflicient valve capacity or leakage paths. After two of the valves in each of the translating apparatus have become conducac tive the translating apparatus and transmission system will continue to function in its normal manner.

It has been suggested that a direct current neutral wire be utilized to interconnect the neutral points of the networks of each of the translating systems in order to obviate the difficulties of starting the transmission system, but when this ire is added it has the disadvantage that the direct current ripple is only m phase or of the to fundamental frequency. In accordance with my invention a starting impedance or resistance is connected between the neutral points of the inductive network and the ground in each electric valve translating system so that this impedance ccoperates with the line-to-ground capacitance of the transmission line to permit the necessary number of valves in each translating system to become conductive. As the same time the advantage of obtaining a 2m phase direct current voltage ripple is maintained.

It is therefore an object of my invention to provide a transmission system utilizing electric valve translating or converting apparatus which will overcome certain limitations of the arrangements of the prior art, and which will be simple m and reliable in operation.

It is another object of my invention to provide an arrangement for facilitating the starting of the electric valve translating apparatus in a direct current transmission system. 15

The novel features which are believed to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation together with further objects and advantages thereof, will be better understood by reference to the following description taken in connection with the accompanying drawing in which Fig. 1 shows a direct current transmission system utilizing a plurality of electric valve translating apparatus employing the valves of the type described by Erwin Marx in the reference referred to above; and Fig. 2 discloses the application of my invention to a direct current transmission system utilizing a different arrangement of electric valve translating system in which there are employed valves of the type in more common use in the art at the present time.

Referring now more particularly to Fig. l of the drawing, there is disclosed an arrangement embodying my invention for transmitting energy from the alternating current supply circuit ID to the alternating current load circuit H by means of an electric valve translating apparatus :2, a direct current transmission line #3 and an electric valve translating apparatus I4. The electric valve translating apparatus l2 includes a trans former having a primary winding I5 connected to the alternating current supply circuit in, and a 45 secondary winding l 6 arranged in star relation so as to provide a neutral point. The outer extremities of the secondary winding l6 are each con nected to both sides of the direct current transmission line l3 by means of a plurality of pairs of valves ll, l8; I9, 20; 2!, 22. Thus the valves 17,19 and 2! are connected to one side of the direct current transmission line l3 through a suitable smoothing reactor 23 and the remaining valves i8, 20 and 22 are connected through a suitable smoothing reactor 24 to the other side of the direct current transmission line E3. The electric valve translating apparatus l4 receives energy from the direct current transmission line l3 through suitable smoothing reactors 25 and 25, and a plurality of pairs of valves 21, 28; 29, 30; 3!, 32, interconnect the outer extremities of a transformer having a primary winding 33 with the direct current circuit. This transformer is provided with a secondary winding 34 which is connected to the alternating current load circuit H. While for the purposes of illustration I have shown the electric valves H to 22 and 2! to 32 as being of the type described by Erwin Marx since such systems utilizing valves of this type appear to be more diflicult to start than those using other types of valves, it of course will be understood that the invention is equally applicable to systems using any of the valves commonly utilized in the art. The valves shown in Fig. 1 comprise two principal electrodes and an auxiliary or starting electrode and a gaseous fluid medium is circulated between the principal electrodes. In accordance with my invention the neutral point of the transformer winding it of the electric translating apparatus I2 is connected to the ground through a resistor or impedance 35, and similarly the neutral point of the transformer winding 33 of the electric valve translating apparatus M is connected through a suitable resistor or impedance S5 to the ground. The capacitance-to-ground of each of the conductors of the transmission line 53 is represented by capacitors 3'11 and 38 shown in dotted lines. pedances 35 and 3B cooperate with capacitances 31 and 38 to provide during the starting operation of the transmission system a leakage path suiiicient to facilitate the starting of the transmission system. It will be apparent to those skilled in the art that the difficulty of obtaining absolute synchronism in the moment of ignition of two of the valves of the translating apparatus 52 for example, is the cause of some of the difiiculty encountered in placing the transmission system into operation. In addition to this difiiculty it is also apparent that the moment of ignition of any pair of valves of the translating apparatus i4 is generally phase displaced with respect to the moment of ignition of a similar pair of valves in the translating apparatus l2. The leakage path provided by the impedances 35 and 33 thus permits in the arrangement shown two valves in each of the translating apparatus to become fully conductive so that normal operation of the transmission system will continue.

In Fig. 2 I have shown the application of my invention to a direct current transmission system operating between the alternating current supply circuit 56 and the alternating current load circuit M. This system includes an electric valve translating or rectifying apparatus 2, a direct current transmission line 3 and an electric valve translating or inverting apparatus A l. The electric valve translating apparatus 42 includes a transformer having a primary winding l5 connected to the alternating current source it and a pair of secondary windings 56 and ll.

The neutral point of the secondary transformer winding is connected to one side of the direct current transmission line 53 through a suitable smoothing reactor G8, and the outer extremities of this transformer winding are connected through a plurality of valves 39, 5t] and 56 to the neutral point of the transformer secondary winding ll. The outer extremities of this The imlatter transformer winding 41 are each connected by one of a plurality of valves 52 to 54 through a suitable smoothing reactor 55 to the other side of the direct current transmission line 43. One side of the direct current transmission line 53 is connected through a suitable smoothing reactor 56 to the neutral point of one of the primary windings 5? of a transformer having a second primary winding 58 and a secondary winding 59 which is connected to the alternating current load circuit 4!. The outer extremities of this primary winding 57 are each connected through one of a plurality of valves 60 to 62 to the neutral point of the other primary winding 58 of this same transformer. The outer extremities of this latter winding 58 are each connected to one of a plurality of valves 63 to 65 through a suitable smoothing reactor 66 to the other side of the direct current transmission line 43. In accordance with my invention I connect an electric translating apparatus 42 and impedance 6'7 between the neutral points of the transformer winding ill and the ground. This point of connection, as will be apparent from an inspection of the circuit arrangement, is a connection between the midpoint of the electric valve translating apparatus and the ground. This impedance 61 cooperates with the capacitance-to-ground of the transmission line d3 indicated by the capacitors S8 and 69 to provide a leakage path across each 7 of the valves and their associated inductive networks. Similarly, an impedance or resistance 79 is connected between the neutral points of the transformer winding 58 and the electric valve translating apparatus 5 5 and the ground to provide the necessary leakage paths which include the capacitances 68 and E9 or" the direct current transmission line 48. It is preferable in either of the circuit arrangements disclosed in the drawing to select impedance devices having a relatively high resistance value since it is only necessary to pass a minimum current sufficient to permit the valves to start.

While my invention has been described as applied to a transmission system, it will be apparent to those skilled in the art that it is equally applicable to a full wave rectifier and in this instance a resistor or impedance is connected between the neutral point of the'electric valve converting apparatus and the neutral point on the load circuit. It will furthermore be apparent that if the capacitance of the transmission line to ground is insufiicient additional capacitors may be utilized or a high impedance may be connected across the transmission line, the neutral point of which is grounded.

While I have shown particular applications of my invention to electric transmission systems, it is to be understood that this is merely illustrative as to but a few of the electric valve transmitting apparatus and transmission systems to which my invention may be applied, It will, of course, be understood that I do not wish to be limited thereto, since it is apparent that the principles herein disclosed are susceptible of numerous other applications, and modifications may be made in the circuit arrangements to which my invention may be applied without departing from the spirit and scope of my invention as set forth in the appended claims.

What I claim as new and desire to obtain by Letters Patent of the United States is:

l. The combination comprising a supply circuit, a load circuit, a plurality of electric valve translating apparatus and a transmission line interconnecting said circuits, each of said translating apparatus comprising an inductive network provided with a neutral point and a plurality of pairs of series-connected electric arc discharge valves connected across said transmission line and an impedance means for each network connected between the neutral points thereof and the ground, said impedances cooperating with the capacitance-to-ground of said transmission line to facilitate the starting of said translating apparatus.

2. The combination comprising an alternating current circuit, a direct current circuit, one of said circuits having an appreciable capacitance-to-ground, an electric translating appara tus interconnecting said circuits and comprising an inductive network provided with a neutral point, and a plurality of pairs of electric are discharge valves connected in series across said direct current circuit, and impedance means for said network connected between the neutral point thereof and the ground, said impedance cooperating with the capacitance-to-ground of one of said circuits to facilitate the starting of said translating apparatus.

3. The combination comprising a supply circuit, a load circuit, a plurality of electric valve translating apparatus and a transmission line interconnecting said circuits, each of said translating apparatus comprising an inductive network provided with a neutral point and a pair of electric arc discharge valves interconnecting each terminal of said network with both sides of said transmission line, and means for facilitating the starting of the valves of said apparatus comprising a plurality of impedances each connected between the ground and the neutral point of each inductive network.

4. The combination comprising a supply circuit, a load circuit, a plurality of electric valve translating apparatus and a transmission line interconnecting said circuits, each of said translating apparatus comprising an inductive network provided with a neutral point and a pair of electric arc discharge valves interconnecting each terminal of said network with both sides of said transmission line, and an impedance means for each network connected between the neutral point thereof and the ground, said impedances cooperating with the capacitance-to-ground of said transmission line to facilitate the starting of said translating apparatus.

5. The combination comprising alternating current supply and load circuits, a plurality of electric valve translating apparatus and a direct current transmission line interconnecting said circuits, each of said translating apparatus comprising an inductive network provided with a neutral point and a pair of electric arc discharge valves interconnecting each terminal of said net work with both sides of said direct current transmission line, and an impedance means for each network connected between the neutral point thereof and the ground, said impedances cooperating with the capacitance-to-ground of said transmission line to facilitate the starting of the valves of said translating apparatus.

HANSI-IEINRICH VERSE. 

